Universal knurling tool



`Iuly 27, 1954 C. H. FROBERG, JR

UNIVERSAL KNURLING TOOL Filed Sept. 21. 1950 nventor Gttorneg FIG. lo.

Patented July 27, 1954 UNITED S'lnllrl EXTENT @ENCE UNIVERSAL KNURLING TOOL Charles Henry Froberg, Jr., Brentwood, N. Y.

Application September 21, 1.950, Serial No. 186,009

8 Claims.

This invention relates to a universal knurling tool, that is, to a knurling tool which can be variously tted to the tail stock of a lathe, or to the turret ci a Fox lathe or turret lathe, or to a hand screw machine, and which is both adjustable and reversible to knurl either a male or a female knurl of varying length upon work of diierent sizes, thus combining in one single device a tool which can be utilized for a large variety of purposes.

011e object ci this invention is a universal knurling tool.

Another object is a knurling tool which by a mere reversal of parts can be rapidly converted from a tool for making male knurls into a tool for making female knurls, and back again.

Another object is a knurling tool capable of forming either a male or a female knurl of any desired length7 upon work of any desired size.

Another object is a knurling tool having a series of detachahly attachable interchangeable and reversible parts, whereby the knurling tool can be utilized for many different purposes, thereby substantially reducing the number of knurling tools which are needed to fully equip a machine shop with a complete range of knurling tools, capable ci performing a substantially endless variety oi knurling operations.

Another object is a knurling tool of but few, simple, and rapidly interchangeable parts.

Another object is to eilect substantial savings in the cost oi equipping a machine shop with knurling tools having a wide eld of use.

Another object is a knurling tool of but few and simple parts which can be readily assembled, disassembled, repaired, replaced, interchanged, and reassembled, to perform a wide range of functions, and which is very enicient and durable in use.

Another object is a knurling tool which automatically releases the cutter to prevent injury thereto.

Other objects will appear from the detailed description which follows:

In the drawing comprising one sheet of ten figures, numbered Figs. l to inclusive, certain embodiments of my invention, in the forms at present preferred, are variously set forth.

Fig. l is a side View of the knurling tool when asseincled to cut a male knurl;

Fig. 2 is a front end View of the assembly of Fig. l;

Fig. 3 is a side View of the knurling tool when assembled in reverse to out a female knurl;

Fig. 4 is an enlarged cross-section of a fragment taken along the line 4-4 of Fig. 1, looking in the direction of the arrows;

Fig. 5 is an enlarged cross-section of a fragment taken along the line 5 5 of Fig. l, looking in the direction of the arrows;

Fig. 6 is an enlarged cross-section of a fragment of Fig. 5;

Fig. '7 is an enlarged end View partly in crosssection taken along the line l-'l of Fig. l, looking in the direction of the arrows;

Fig. 8 is a cross-section taken along the line il-S of Fig. 7, looking in the direction of the arrows;

Fig. 9 is an enlarged cross-section of a fragment taken along the line 9-9 of Fig. 1, looking in the direction of the arrows; and

Fig. 10 is a side View of a fragment of an assembly, showing a modified form of the invention.

Like reference characters designate corresponding parts throughout the several gures oi the drawing.

The knurling tool 2li includes the box 2l which supports two adjustable arm blocks 22 and 23 which carry the arrns 2d and 25. The knurls 26 and 2l are rotatably mounted upon the sleeves or bushings 28 and 20 between the upper jaw 30 and lower jaw 3l of the arm 2li or 25. rlhe knurls 26 and 2l and the sleeves 28 and 29 preferably are made of steel of the same quality, such as tool steel, so that each sleeve is as hard as its associated knurl.

The box 2l is elongated and is bored from bottom to top and counterbored from the bottone to provide a, hole which is then female threaded at 32 to receive the male threaded end 63 ora shank 3ft. Shanks of various sizes and either straight 35 (Fig. 3) or tapered 36 (Fig. l) may be provided, which may be used interchangeably so that the knurling tool 2li may be tted to the tail stock 3l of a lathe, or to the hole in the turret of a Fox lathe (not shown), or tted so that it may be used with a hand screw machine (not shown) or in the turret of a turret lathe (not shown), all of which devices are well-known in the art. A clamping holder 38 provided with a split lug lug 39 threaded at fill and an Allen locking screw #il capable of being tightened to secure the holder. upon the spindle of the tail stock or tail stand 3l of a lathe, may alsobe provided. lljhe hole through the box 2li permits the work 42 to feed through the knurling tool'as the work 42 is knurled thus permitting the knurl-l ing of a substantial length of the work t2. Y

Either straight cut or diagonally cut knurls may be mounted interchangeably upon the sleeves 28 and 25 dependent upon whether it is desired to cut a straight or diamond patterned knurl upon the work.

An inverted T-shaped channel l5 is out cross wise in the top of the box 2l to receive and acn commodate the arm blocks 22 and 23 which are each provided with an inverted T-shaped iin or tongue 44 whose several dimensions are slightly smaller than the corresponding dimensions of the T-shaped channel i3 formed in the box 2i, to provide sliding clearance 'for the tongues when positioned in the channels d3.

Each arm block 22 or 23 may be made in twopieces consisting of an arm holder i5 and an arm 25 or 25 which is seated in a channel 5 formed in the upper edge face of the armV holder 45. The arm 2:1; or 25 is fastened in the channel 46 by means or Allen screws Ill positioned in counterborecl holes 55 which are threaded at 55 toreceive the Allen screws lll. rThe rack is push fitted in the slot l which overlies the heads of. the Allen screws 4l. The rack 55 can be pried out. of the slot 5l as by means of a screw-driver.

By making the arm blocks 22 and 23 in two pieces, narrower stock can be used to form the arms 25 and 25 than is necessarily required to maker the arm holders 45. If the arm 24 or '55 and arm holder l5 were made in one piece, would be necessary to use stock as wide as the arm holder l5 which is approximately double the width of the arms 25 and 25, and then mill away a large part of the stock to fashion the arm 24 or 25. By making the arms separately, interchangeable pairs of detachably attachahie arms of diferent lengths may be provided, and by selecting longer or shorter arms for mounting inthe channels llt of the arm holders l5 different lengths of work l2 may be knurled.

The knurl 2li or 2l and sleeve 28 or 25 may be hardened to a specified degree of hardness as for example according to the Rockwell scale. Because the sleeves 28 and 29 and their associated knurls 25 and 2T are equally hard, the rotation of the knurl about the sleeve will not weer out the sleeve.

Each arm 24 and 25 is provided with a sleeve hole 52 slightly larger in diameter than the outu side diameter of the sleeve 25 or 29 for clearance. This prevents the sleeve from freezing its sleeve hole, and facilitates easy removal and renewal of the sleeve 23 or 29. By making the sleeve hole 52 slightly larger than the outside diameter of the sleeve, any strain upon the ab len screw 53 as it draws the sleeve into the sleeve hole 52 is eliminated, thus relieving tension unen, andreducing the risk ofv stripping, the thread of the Allen screw 55.

The sleeves 2B and 29 are female threaded at 54 to receive the male threaded stern 55 of a screw 53 which has an Allen head whose outside diameter is preferably the same as the outside diameter of the sleeves 2S and 29. Preferably each thread of the female thread 55 of the sleeve 28 or 29 is flat at the peak 55 and sharp at the root 5l thereof, while the stem 55 of screw 53 is provided with a sharp thread 55. The flat peak 56 makes the sleeve 2S or 23 easier to tap and insures that the sleeve cannot freeze to the sharp thread of the male threaded stem 55 of the screw 53. The sleeve hole 52 is drilled and tapped at 55 to receive the male threaded stern 55v ofthe Allen head screw 53. The threaded hole 59 is deep enough to allow clearance for the end of the stein 55 of the Allen head screw 53,

So that the stem 55 of the screw 53 cannot lock in the bottom of the hole 55. The screw 53 is not as hard as its sleeve 25 or 25, so that if the stem 55 breaks oir in the hole 59, the broken stern 55 of the screw 53 being softer than tool steel can always be drilled out and the broken screw replaced.

if for any reason, such as lack of lubrication, or the entrance of a burr the knurl 25 or 2l freezes upon its sleeve 28 or 29, the sleeve will revolve with the knurl to unscrew the Allen head screw 53.

The box 2l is equipped with two shafts 55 and El for mounting pinion gears 52 and 55, each pinion gear being adapted to mesh with a rack 55 push fitted to and removably nesting in a slot 5I cut in the underface of its associated arm holder 55, so when the shaft 56 or 5I is turned to rotate the pinion gear 62 or 53, the rack 55 in mesh with the pinion gear .J2 or 53 slidably adjusts the position of the arm holder 55 relative to the box 2i, to adjust the spacing between the knurls 25 and El according to the diameter of the work 42 which is to be knurled. rllhe arm. blocks 22 and 23 are reversible in the hex 2l (compare Figs. l and 3), so that a male knurl 5ft may be formed upon a rod ll?. or the like, or an internal or female knurl 55 be formed upon the internal wall or inner-face of ring 56 or the like.

The box 2i is bored at 5l at spaced intervals to receive the shafts 55 or 5I of the pinion gears 52 or 53, and is counterbored at 55 from one side to receive the pinion gears 62 and 63 and to nest the enlarged head 53 of the shaft S0, which is free to rotate therein. The shoulder l' on the end of the enlarged 53 seats against the face of the box 2! to position the pinion gear 52 or 53 relative to the rack. The box is counterbored at 'll from the opposite side to receive a thrust washer 'I2 which is press iitted upon the shaft 55 or 5l and turns therewith in the bearing formed by the eounterbored opening ll. Each pinion gear or 53 is detachably mounted upon the shaft 55 or 5I and is provided with a boss 'I3 which is slotted at "Hl to receive a crosspin l5 which is pinned through the shaft 55 er Si so that when the crosspin 'l5 engages the slot 'i5 in the boss l@ the pinion gear 52 or 53 is locked upon the shaft. The head 5d of the shaft 55, 5l is provided with an Allen socket l5 to receive an Allen adjusting wrench for turning the shaft 55 or 5i and its associated pinion gear 52 or 55 which being in mesh with the rack moves the arm block 22 or 23 in or out to adjust the spacing between the knurls 25 and 2l to work of any size within the working limits of the knul-ling tool 25. The blocks 22 and 23 when adjusted may be locked in selected position by applying tension to the grub screws 'il which are threadably mounted in the holes l which are drilled and tapped in the box 2l at right angles to the inverted T-shaped channel 53. The grub scr ws il are adiustable to force the soft metal plugs 'i5 which are fitted upon the ends of the grub screws 'il against the 'face or the side wall of the tongue M to prevent any change of position of the arm block 2?. or 23 until such time as its associated grub screw 'Il is loosened to remove pressure from the metal plug 19. The plugs le are made of brass or other soft metal so that the plug will not mutilate the face of the tongue 55. The plug 'I9 is .ong enough so that when pushed outwards against the tongue 44 the plug will not fall out of the tap clearance hole.

The face of the box may be provided at 8i! and 8i with calibration points which may be read against the scale markings 82 and 33 which may be calibrated upon the edge faces of the arm holders d so as to furnish any preferred system of scale readings indicative of the spacing between the knurls and/or of the diameter of the Work which the kiiurls are set to lznurl.

By making the arm blocks 22 and 23 reversible and providing pairs of arms 24 and 25, of diierent lengths, by providing interchangeable knurls, a wide range of knurling tools of difierent sizes and which can be used for various purposes can be developed by mounting the proper knurls in a pair of arms of the proper length upon the arm holders i5-45 and. by mounting the arm holders 435--45 upon the box 2l to form a tool capable of making either a male knurl @Il or a female knurl G5 thus producing a knurling tool which can be utilized for many diiierent purposes and for knurling a large variety of work and many sizes thereof, thereby effecting substantial economies in the cost of equipping a machine shop with a wide range of knurling tools.

What is claimed is:

l. In a knurling tool and in combination, an elongated carrier having a T-shaped channel formed in and extending along the top thereof, a central opening formed in the bottom of the carrier and merging with said channel, said opening being female threaded, a pair of arm bloei/is, each arm block having a T-shaped tongue formed at the lower end thereof conforming in reverse conilguration to the shape of but slightly smaller in dimensions than the T-shaped channel whereby said tongues engage in said channel with suicient clearance to eect a sliding and vary the spacing between said arm blocks, a pair of arms, each arm being formed from metal stoel: substantially thinner than the arm blocks, each arm block having a channel form-cd therein for seating one of said arms upon said arm block, screws extending through said arm blocks and into said arms for detachably securing said. arm to its saidarrn block, each arm being bifurcated at its upper end, a pair of knurling rolls, said knurling rolls being oppositely rotatably mounted in spaced relation between the forks of the bifurcated upper ends of their respective arms, said T-shaped tongues being reversible end for end in the T-shaped channel to selectively position said lrnurling rolls for cutting either male or female knurls, and means including a rack and pinion for sliding the arrn blocks to and fro along the T-shaped channel to vary the spacing between the lrnurls.

2. In a knurling tool and in combination, a knurl supporting said arm being bifurcated at the upper end thereof to form upper and lower spaced jaw members, said lower jaw having a bored and counterbored hole formed therein, said upper jaw having a hole therein concentric with said counterbore, a lrnurl having a central opening iorrned therein substantially equal in diameter to the diameter of said counterbore, and means for detachably rotatably mounting said knurl between said spaced jaw members comprising a sleeve extending through the central opening in said lnurl and nesting in said counterbore with suiilcient clearance to effect a sliding t and to axially align the opening in the sleeve with the hole bored in said lower jaw, a machine screw having an enlarged Allen head journalled to rotate in the hole in the upper jaw, the sleeve and. the hole bored in the lower jaw being threaded to receive the threaded stem of said screw, the stem of said screw being shorter than the combined length of the sleeve and the threaded hole to eliminate freezing of the screw in said hole, and the metal composing said screw being of lesser hardness than the metal composing said sleeve and said jaw members.

3. In a knurling tool and in combination, a knurl supporting arm, said arm being bifurcated at the upper end thereof to form upper and lower spaced jaw members, said lower jaw having a bored and counterbored hole formed therein, said upper jaw having a hole therein concentric with said coimterbore, a knurl having a central opening formed therein substantially equal in diameter to the diameter of said counterbore, and means for detachably rotatably mounting said knurl between said spaced jaw members comprising a sleeve extending through the central opening in said knurl and nesting in said counterbore with sufficient clearance to effect a sliding nt and to axially align the opening in the sleeve with the hole bored in said lower jaw, a machine screw having an enlarged head journalled in the hole in the upper jaw, the sleeve and the hole bored in the lower jaw being threaded to receive the threaded stem of Said screw, the stem of said screw being shorter than the combined length of the sleeve and the threaded hole to eliminate freezing of the screw in said hole, and the metal composing said screw being of lesser hardness than the metal composing said sleeve and said jaw members.

e. ln a linurling tool and in combination, an bifurcated at its free end to form an upper and a lower jaw member, said jaw members being arranged in oppositely spaced relation, an axle supported between said jaw members, said axle including a sleeve and a machine screw having an enlarged head and having a stein longer than said sleeve, said sleeve being internally threaded, the stein of said screw passing through said sleeve with a screw t and projecting beyond the end oi said sleeve to complete said axle, said jaw members having axially aligned holes formed therein deiining bearings for supporting the opposite ends of said axle, the hole in said lower jaw member being stepped at its inner end, the inner end of said hole being longer than, and being internally threaded to receive, the projecting end of the stern of said screw, said screw being variously operable to draw said sleeve into and out of said bearings, a lrnurl rotatably supported upon said axle, said sleeve being tempered to substantially the same degree oi hardness as said knurl, and said screw being tempered suiiiciently sorter than the sleeve and the knurl to facilitate removal of a broken screw.

5. In a knurling tool and in combination, an elongated carrier having a T-.shaped channel formed in and extending along the top thereof, a central opening formed in the bottom of the carrier and merging with said channel, said opening being female threaded for attachment to different interchangeable inale threaded carrier supporting Shanks, a pair of arm blocks, each arm block having a T-shaped tongue formed at the lower end thereof conforming in reverse configuration to the shape of but slightly smaller in dimensions than the T-shaped channel where-l by said tongues slidably engage said channel and are movable therealong to vary the spacing between said arm blocks, each arm block having a 

